基于组合相关函数的AltBOC(15,10)信号的无模糊跟踪方法

Unambiguous tracking method of AltBOC(15,10)signal based on combined correlation function

针对由于自相关函数的多峰性质导致的交替二进制偏移载波(AltBOC)(15,10)信号的跟踪模糊问题提出一种基于组合相关函数的无模糊跟踪方法。首先设计了两个特殊的本地信号,然后通过码跟踪环路实现本地参考信号与接收信号的相关运算,从而获得两个互相关函数,最后将这两个互相关函数相乘以获得无模糊相关函数来消除模糊问题。分析了该方法的热噪声跟踪精度以及抗多径干扰性能,结果表明:1)该方法实现了无模糊跟踪;2)其跟踪精度介于类二进制相位键控(BPSK Like)方法和伪相关函数(PCF)法之间,当载噪比大于40 dB·Hz时跟踪精度与PCF方法相当;3)当多径延迟大于0.1个码片时,多径误差明显小于BPSK Like方法和PCF方法。

Aiming at the tracking ambiguity of Alternate Binary Offset Carrier(AltBOC)(15,10)signal caused by the multi-peak of autocorrelation function,an unambiguous tracking method based on combined correlation function was proposed.Firstly,two special local reference signals were designed in this method,then the correlation operations between the local reference signals and the received signals were realized through the code tracking loop to obtain two crosscorrelation functions,and finally the ambiguity was eliminated through the unambiguous correlation function which is the multiplication of the two obtained cross-correlation functions.The tracking accuracy under thermal noise and anti-multipath interference performance of the proposed method were studied.The results show that:1)the proposed method realizes the unambiguous tracking;2)the tracking accuracy of the proposed method is between Binary Phase Shift Keying Like(BPSK Like)method and Pseudo Correlation Function(PCF)method,and the tracking accuracy of the proposed method is nearly close to that of PCF method when the noise ratio is greater than 40 dB・Hz;3)when the multipath delay is greater than 0.1 code chip,the proposed method has the multipath error significantly smaller than that of BPSK Like method and PCF method.